This invention relates to a gas cooler and process for cooling a hot raw gas stream and for simultaneously producing saturated and/or superheated steam. More particularly, it relates to a gas cooler and process for extracting heat from the hot raw gas stream from the partial oxidation process, and the simultaneous production of a separate stream of saturated or superheated steam, or separate streams of both.
Synthesis gas, reducing gas and fuel gas are commonly produced by the partial oxidation of gaseous and liquid hydrocarbonaceous fuel, and from solid carbonaceous fuel. For example, reference is made to the partial oxidation processes described in coassigned U.S. Pat. No. 3,620,699; 3,639,261; and 3,998,609.
The raw effluent gas stream comprising H.sub.2, CO and entrained particulate matter leaves the reaction zone of the partial oxidation gas generator at a temperature in the range of about 1700.degree.-3000.degree. F. and a pressure in the range of about 1 to 250 atmospheres. The raw gas stream may be cooled to a temperature in the range of about 600.degree. F. to 1200.degree. F. by indirect heat exchange with water in a gas cooler or waste heat boiler. By-product saturated steam may be thereby produced. The saturated steam is often superheated in outside equipment, such as a fired heater. In coassigned U.S. Pat. No. 4,099,382, saturated steam that is produced in a downstream heat exchanger is recycled and superheated in another heat exchanger that is located upstream from the downstream heat exchanger. In coassigned U.S. Pat. No. 4,247,302, saturated steam is produced in one or more shell-and-straight fire tube gas coolers and then superheated in another shell-and-straight fire tube gas cooler. A waste heat boiler with helical cooling tubes whose ends are in communication with water cooled gas inlet pipes is described in U.S. Pat. No. 4,029,054. Cooling the inlet ends of gas tubes by means of a coolant is described in U.S. Pat. No. 3,610,329.